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17.1F: Genetically Modified Organisms (GMOs) - Biology

17.1F:  Genetically Modified Organisms (GMOs) - Biology



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Transgenic modification, adding recombinant DNA to a species, has led to the expression of desirable genes in plants and animals.

Learning Objectives

  • Describe how research on transgenic plants and animals aids humans.

Key Points

  • Transgenic animals are those that have been modified to express recombinant DNA from another species.
  • Manipulation of transgenic plants, those that have received recombinant DNA from other species, has led to the creation of species that display disease resistance, herbicide and pesticide resistance, better nutritional value, and better shelf-life.
  • The thickness of a plant’s cell wall makes the artificial introduction of DNA into plant cells much more challenging than in animal cells.

Key Terms

  • transgenic: of or pertaining to an organism whose genome has been changed by the addition of a gene from another species; genetically modified
  • genetically modified organism: an organism whose genetic material has been altered using genetic engineering techniques

Transgenic Animals

Although several recombinant proteins used in medicine are successfully produced in bacteria, some proteins require a eukaryotic animal host for proper processing. For this reason, the desired genes are cloned and expressed in animals, such as sheep, goats, chickens, and mice. Animals that have been modified to express recombinant DNA are called transgenic animals. Several human proteins are expressed in the milk of transgenic sheep and goats, while others are expressed in the eggs of chickens. Mice have been used extensively for expressing and studying the effects of recombinant genes and mutations.

Transgenic Plants

Manipulating the DNA of plants (or creating genetically modified organisms called GMOs) has helped to create desirable traits, such as disease resistance, herbicide and pesticide resistance, better nutritional value, and better shelf-life. Plants are the most important source of food for the human population. Farmers developed ways to select for plant varieties with desirable traits long before modern-day biotechnology practices were established. Plants that have received recombinant DNA from other species are called transgenic plants. Because foreign genes can spread to other species in the environment, extensive testing is required to ensure ecological stability. Staples like corn, potatoes, and tomatoes were the first crop plants to be genetically engineered.

Transformation of Plants Using Agrobacterium tumefaciens

Gene transfer occurs naturally between species in microbial populations. Many viruses that cause human diseases, such as cancer, act by incorporating their DNA into the human genome. In plants, tumors caused by the bacterium Agrobacterium tumefaciens occur by transfer of DNA from the bacterium to the plant. Although the tumors do not kill the plants, they stunt the plants, which become more susceptible to harsh environmental conditions. Many plants, such as walnuts, grapes, nut trees, and beets, are affected by A. tumefaciens. The artificial introduction of DNA into plant cells is more challenging than in animal cells because of the thick plant cell wall.

Researchers used the natural transfer of DNA from Agrobacterium to a plant host to introduce DNA fragments of their choice into plant hosts. In nature, the disease-causing A. tumefaciens have a set of plasmids, called the Ti plasmids (tumor-inducing plasmids), that contain genes for the production of tumors in plants. DNA from the Ti plasmid integrates into the infected plant cell’s genome. Researchers manipulate the Ti plasmids to remove the tumor-causing genes and insert the desired DNA fragment for transfer into the plant genome. The Ti plasmids carry antibiotic resistance genes to aid selection and can be propagated in E. coli cells as well.

The Organic Insecticide Bacillus thuringiensis

Bacillus thuringiensis (Bt) is a bacterium that produces protein crystals during sporulation that are toxic to many insect species that affect plants. Bt toxin has to be ingested by insects for the toxin to be activated. Insects that have eaten Bt toxin stop feeding on the plants within a few hours. After the toxin is activated in the intestines of the insects, death occurs within a couple of days. Modern biotechnology has allowed plants to encode their own crystal Bt toxin that acts against insects. The crystal toxin genes have been cloned from Bt and introduced into plants. Bt toxin has been found to be safe for the environment, non-toxic to humans and other mammals, and is approved for use by organic farmers as a natural insecticide.

Flavr Savr Tomato

The first GM crop to be introduced into the market was the Flavr Savr Tomato, produced in 1994. Antisense RNA technology was used to slow down the process of softening and rotting caused by fungal infections, which led to increased shelf life of the GM tomatoes. Additional genetic modification improved the flavor of this tomato. The Flavr Savr tomato did not successfully stay in the market because of problems maintaining and shipping the crop.


The EU regulatory framework on genetically modified organisms (GMOs)

The European Union (EU) legislation on genetically modified organisms (GMOs) aims to ensure a high level of protection for human, animal and environmental health and a well-functioning EU internal market. The framework regulates the release of GMOs into the environment and their use as, or in, food and feed. It has three main pillars: pre-market authorisation based on a prior risk assessment, traceability and labelling. Within this legal framework, the EU has authorised the placing on the market of 118 GMOs so far. These have been obtained through long-standing techniques of genetic modification, namely transgenesis. Following the adoption of the GMO legislation, new techniques of genetic modification, including new mutagenesis techniques, have been developed, which have raised questions regarding the applicability of the GMO legislation and attracted a lot of attention from stakeholders and the general public. This article provides an overview of EU GMO legislation and implementation of the EU Court of Justice ruling on organisms obtained by mutagenesis techniques, issued in July 2018. It also updates on the recent initiatives by the European Commission and EU Member States on new developments in biotechnology. The manuscript is based on the author's contribution at the OECD Conference on Genome Editing, Applications in Agriculture, Implications for Health, Environment and Regulation held in Paris on 28-29 June 2018. It is complemented with updated information.

Keywords: European Union Gene drive Genetically modified organisms Mutagenesis Regulatory framework Synthetic biology.


Genetically Modified Organisms.

In an excellent BBC interview with some anti-GMO protesters destroying a field of research crops some young people were asked to explain why they were taking this action. None of those interviewed could explain what the risks of GMO crops are. The field represented years of research by a geneticist trying to find new crop varieties to feed a growing world population. The young protesters had a right to protest but also.

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Understanding the biology behind GMOs can help consumers evaluate GMO safety

What are GMOs (genetically modified organisms) and are they safe to eat? It can be difficult for a consumer to sort through and understand the information in the media and on food labels regarding food production methods and food safety. When it comes to GMOs, which refer to genetically modified (GM) crops resulting from a modern breeding method called genetic engineering, there is a great deal of information. Some information is accurate, some not, and some misleading. However, according to a Pew survey, there is much agreement among scientists about the safety of GMO plants and products for human consumption.

Based on hundreds of research studies, more than 280 food safety agencies, and scientific and technical institutions throughout the world (Table 1), support the safety of GMO technology (genetic engineering) to modify traits in plants. This includes the Food and Drug Administration (U.S. FDA), the European Food Safety Authority, and the World Health Organization. Despite the scientific consensus on safety, consumer concerns abound. Such concerns often include environmental, agricultural production, economic, and social justice aspects. This article deals specifically with food safety.

National Academy of Sciences - May 2016

Society of Toxicology - September 2002 - Consensus position statement

National Research Council - National Academy of Sciences

American Medical Association

Institute of Food Technologists

American Dietetic Association

European and International

France - French Academy of Medicine - 2003

Italy - Eighteen scientific associations - October 2004 (including National Academy of Science, Societies for Toxicology, Microbiology, Nutrition, Biochemistry) signed consensus statement on safety of GMO crops

FAO - Food and Agriculture Organization

WHO - World Health Organization

International Council for Science - 2005, 2010 (111 National Academies of Science and 29 scientific unions)

What is a GMO?

Some people cringe at the words &ldquogenetically modified organism&rdquo, but genetic modification is an important method people have used for the past 10,000-30,000 years while they domesticated both crops and animals. When plants and animals are selectively mated, the genes from both parents are mixed and many inherited traits are changed, which can be readily observed in the wide varieties of certain species, such as dog breeds. Without much knowledge about genetics, plants and animals were purposefully changed when people observed differences in plants and animals, and then mated what appeared to be the &ldquobest&rdquo ones to create and/or preserve beneficial traits and characteristics.

Today, several different breeding methods are used to improve plants, including the traditional methods (when possible). Regardless of method, all involve modifying the genetic makeup, or genes, of an organism. All living organisms -plants, animals, microbes- have genes, and all genes are made of DNA (Deoxyribonucleic Acid), which is the universal coding system that determines traits such as crop yield, height, hair color, horns, etc.

In contrast to a plant created by modifying its DNA using traditional breeding methods, a GMO plant is created using a newer, more controlled method referred to as genetic engineering. This method changes plants by inserting a gene from another organism to add a useful trait to the recipient organism, such as disease or pest resistance. With genetic engineering, the DNA can come from organisms that cannot mate with the crop being modified, e.g., bacteria, fungi or another crop or unrelated plant. For example, one might move a drought tolerant gene from a drought tolerant plant to a corn plant. Since the 1980s, an important GMO is bacteria that have been modified to produce human insulin. These bacteria resulted from inserting the human gene for insulin into the bacteria DNA, so they can produce the human insulin protein. Bacteria produce about 90 percent of human insulin today.

With genetic engineering, usually only one gene from the donor, with a known role or coding for a known protein, is added or inserted into the current set of genes of a recipient plant. In contrast, traditional breeding methods mix many genes (from similar plants) in the mating process. Further, the resulting plants or offspring could have multiple and/or unpredictable outcomes, some of which can be undesirable (e.g., negative impact on yield, quality, or flavor).

Within the past decade, an even more precise method of genetic engineering has been developed called gene editing. This method simply &ldquoedits&rdquo the DNA code of a gene in an organism to modify its expression, instead of introducing a new gene, to give the organism certain characteristics such as more drought tolerant or nutritious. Related techniques can also be used to insert a new gene from another organism into a precise location in the organism&rsquos DNA.

What are Genes and DNA?

Genes provide the instructions for the cells of plants and animals to do their work. Genes are made of units of DNA, represented by the letters A, T, G and C, which form thread-like chains of molecules that look like a twisted ladder (Figure 1). DNA code is similar to the binary code system in computers, which uses &ldquo0&rdquo and &ldquo1&rdquo in different arrangements to create messages or computer instructions. With DNA, combinations of A, T, G, and C form each gene and genes code for various proteins (Figure 1). Proteins in plant and animal cells control various functions of the cell and organism. All methods used to genetically modify plants change DNA, including naturally occurring mutations, resulting in changes in the genetic code. A simple example of a mutation or a change in the code would be changing a G to T. Click here to learn more.

Figure 1. Genes are made of sequences of DNA which form thread-like chains and code for specific proteins that control cell functions.

Are Genes and DNA safe to eat?

Virtually everything we eat comes from a plant, animal, or fungal source. That means it either has genes (DNA) in it or if it was highly processed, such as oil and sugars which no longer contain DNA, it was extracted from an organism that had genes. This means we are constantly eating genes (DNA), whether modified by traditional breeding methods, natural mutations or genetic engineering. Our digestive tract breaks down DNA in the same way, regardless of the source and regardless of the DNA sequence.

Nonetheless, proteins produced by the new genes, and the resultant crop products, must be tested for safety. For this reason, whenever a new plant variety is created using genetic engineering in the U.S., the new variety undergoes rigorous testing for allergens, toxins and modified nutritional content, based on FDA and international food safety standards. All GM products currently on the market have been approved by and are regulated by the FDA. For a greater understanding of testing genetic engineered plants, see a discussion by Professor Robert Hollingworth from the Michigan State University Center for Research on Ingredient Safety (CRIS).

Why use GMO Crops?

All farmers face challenges from insects, disease, weeds and weather in their efforts to cultivate healthy, productive crops. Genetic engineering provides another tool to deal with some of these challenges.

Some examples of traits that have been added to plants using genetic engineering include:

  • Disease resistance
  • Drought resistance
  • Insect resistance
  • Herbicide tolerance
  • Improved nutrition (e.g., adding Vitamin A production in golden rice to prevent deficiencies in third-world countries and increasing protein in cassava)

There are ten crops that have been approved GM varieties in the United States as of 2018:

  • Corn (field and sweet)
  • Soybeans
  • Cotton
  • Alfalfa
  • Sugar beets
  • Canola
  • Papaya
  • Summer squash
  • Innate potatoes
  • Non-browing Arctic apples

In the case of corn, soybeans, cotton, sugar beets, and papaya over 90 percent of the acreage in the U.S. consists of genetically-engineered varieties. Farmers have quickly adopted crops produced by this technology because they reduce losses from pests, and reduce production costs, pesticide use, and the carbon footprint (National Academy of Sciences). For all of the other approved GM crops, only a small proportion is GMO.

Foods in U.S. stores today might contain products from GM corn, soybeans, canola, or sugar beets. However, processed oils or sugars from these crops are refined products and do not contain DNA or proteins.

Summary

The topic of GMOs is very important to many individuals and organizations because it involves questions related to food safety, human health, ecosystem health, and the ability to continue to make genetic improvements of plants. The GMO debate is likely to continue for many years because of the complexity and strong opinions on the topic, as well as the economic impacts that may influence interest groups on both sides of the debate. GMOs continue to be researched, new methods are evolving and with new information, comes new points for discussion.

Understanding some basic biology and the processes of plant breeding can help individuals understand GMOs and their safety. When looking for information, be sure to seek information from institutions and agencies that share science-based, objective results. Several university Extension services are now offering easy-to-use websites for those seeking accessible and reputable information about the safety of GMOs. Michigan State University AgBioResearch devoted an entire issue of its Futures Magazine to: &ldquoThe Science behind GMOs&rdquo. The Food and Drug Administration as well as the World Health Organization also have useful information on GMOs.

Virtually all that we eat today, whether plants or animals, has had its DNA altered by humans for thousands of years. The DNA that is modified consists of the same building blocks (DNA) whether the organism is genetically engineered or not. It is the arrangement of the DNA that makes any altered organism different from another, not if DNA is modified by natural mutation or various breeding methods (traditional breeding methods or genetic engineering).

In a nutshell, genetic engineering in plants is a more recent and more precise method of producing plants with desirable traits. Changing the DNA in plants has no influence on the safety of the DNA because we readily digest the strands of DNA as we always have. The proteins created by the new DNA are tested in accordance with FDA guidelines, to ensure that they are safe to consume.

References:

  • Funk, C., L. Rainie. Public and Scientists&rsquo Views on Science and Society, Pew Research Center. http://www.pewinternet.org/2015/01/29/public-and-scientists-views-on-science-and-society/
  • MSU Today. 2018. GMOs 101. Michigan State University https://msutoday.msu.edu/feature/2018/gmos-101/
  • Sí Quiero Transgénicos. 2017. http://www.siquierotransgenicos.cl/2015/06/13/more-than-240-organizations-and-scientific-institutions-support-the-safety-of-gm-crops/
  • National Academies of Sciences, Engineering, and Medicine. 2016. Genetically
  • Engineered Crops: Experiences and Prospects. Washington, DC: The National Academies Press. doi:10.17226/23395. http://www.nap.edu/23395
  • The Science Behind GMOs. 2018. Michigan State University AgBioResearch. http://www.canr.msu.edu/publications/the-science-behind-gmos

Learn more:

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).

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Future directions for the creation of GMOs

Humans’ ability to modify crops for improved yields and nutrients in a given environment is a keystone of agriculture. The technological advancement from selective breeding to genetic engineering has opened up a large realm of possibilities for the future of our food. As techniques for genetic engineering, such as new RNAi- and nuclease-based technologies that allow for direct modification of the genome (see this article and this article), steadily improve, our ability to create new GMOs will also grow [11]. As our scientific capabilities expand it is essential that we discuss the ethics and ideals surrounding GMOs so that we may effectively and safely use this technology in a way that is acceptable to the public.

Table 1. Summary of the FDA’s Inventory of Completed Biotechnology Consultations on Genetically Engineered Foods as of June 30th, 2015. Crops listed in order of relative abundance of genetically engineered crop consultations (corn having the most consultations). This information is available to the public:
http://www.accessdata.fda.gov/scripts/fdcc/index.cfm?set=Biocon

Chelsea Powell is a PhD student in the Chemical Biology Program at Harvard University.

This article is part of the August 2015 Special Edition, Genetically Modified Organisms and Our Food.


Biology Paper on Genetically modified organisms (GMOs)

Genetically modified organisms (GMOs) are animals, plants, microorganisms or other organisms whose genetic makeup have undergone modification using a recombinant DNA method for gene splicing, modification or the transgenic technologies. This is a relatively new technology which has led to the creation of unstable combinations of animals, plants, viral and bacterial genes that never occur by traditional methods of crossbreeding and in nature (Eastham & Sweet, 2002). This paper discusses various aspects of GMOs.

Safety of GMOs

GMOs are often not considered safe in many countries that are developed. Such nations have also developed major restrictions and outright bans on the sales and production of GMOs. However, nations as the United States and the Canadian government have approved the GMOs based on the studies carried out by the corporations which create them and make profits from the sale. Most nations globally have passed their crucial concerns on the GMO labeling. Sixty-four nations worldwide including Japan, Australia, and all the European Union countries require the labeling of genetically modified foods (Skogstad, 2003). Due to lack of compulsory labeling, non-GMO projects were created to provide the consumers with informed choices (Caswell, 2000).

Foods Containing GMOs

There are various foods which contain GMOs. Most of the foods that are packaged contain the ingredients that are derived from soy, corn, sugar beet and canola. Also, the wide majority of the crops are grown in areas as North America. Most of the crops in such regions are genetically modified (Eastham & Sweet 2002).

Roles of biotech industry in Genetic Modifications

The biotech industry has a key role to play in curbing the challenge of GMO. It has to diversify into other productions as genetic modification of plants is not its only role. The DNA studies hold some promise for most significant applications as medicine. However, current genetically modified food technologies are based on obsolete theories and information and are prone to serious side effects. It has been pushed to the market due to the economic interests. Also, the technology of molecular marker, Marker Assisted Selection (MAS) that is used on conventional breeding has shown great promises for the development of improved crop varieties. The developments would have no potential serious direct genetic modification side effects (Spök, 2007). These industries have assessed the impact of GMOs on the environment.

Environmental impacts of GMOs

The genetically modified foods affect the environment in different ways. More than 75% of the GMOs that are grown globally are often engineered with the tolerance of herbicides. Due to this, the applications of herbicides that are toxic as Roundup have increased 15 times because of GMOs introduction. Genetically Modified crops have also influenced the emergence of super weeds and super bug that are herbicide resistant. The weeds and bugs could therefore only be eradicated using more toxic poisons as 2, 4-D which is a main Agent Orange ingredient. GMOs form direct chemical extensions and are created and sold by the world’s largest chemical organizations. There are adverse long-term effects GMOs to the environment and once released into the atmosphere they organisms are never recallable (Anderson & Nielsen, 2000).

Effect of GMOs to farmers

A part from the effect on the environment GMOs also have various effects on farmers. Since the GMOs are key forms of life, biotechnology organizations have invented ways of obtaining the patents used to restrict their usage. Due to this, the GMO companies now have authority to sue any farmer whose field is contaminated with the GMOs. This would occur even when it would be as a result of neighborhoods field’s drifts. The GMOs are therefore posing serious threats to the sovereignty of farmers and to the national food security of any nation where they would be grown (Anderson & Nielsen, 2000).

I really think and feel the GMOs should never be put let alone labeled on the grocery shops. Thisis due to the fact that these foods have undergone genetic modification which maybe can affect humans. The benefit of GMOs is the high quality and ability to withstand extreme condition. The disadvantage is the impact it might have on people genetic makeup.

Anderson, K., & Nielsen, C. P. (2000). GMOs, Food Safety and the Environment: What Role for Trade Policy and the WTO?. Centre for International Economic Studies.

Caswell, J. A. (2000). Labeling Policy for GMOS: To each his own?

Eastham, K. & Sweet, J. (2002). Genetically modified organisms (GMOs): The significance of gene flow through pollen transfer. Copenhagen: European Environment Agency.

Skogstad, G. (2003). Legitimacy and/or policy effectiveness?: network governance and GMO regulation in the European Union. Journal of European Public Policy, 10(3), 321-338.

Spök, A. (2007). Molecular farming on the rise–GMO regulators still walking a tightrope. TRENDS in Biotechnology, 25(2), 74-82.


Synthetic biology vs. genetically modified organisms

One of the most common objections synthetic biologists confront in their work is that they are essentially dealing with technology that suffers from all the same problems as genetically modified organisms (GMOs).

Brandiff Caron, assistant professor and associate chair of Concordia's Centre for Engineering in Society, says researchers in the field often believe this is an unfair comparison, with many of them arguing that it is the public who has an irrational fear of the unknown around GMOs. This claim, he contends, simply highlights how experts misunderstand the complaints individuals have with genetic engineering.

“The numbers show pretty clearly that people don’t necessarily believe that genetically modified organisms are directly dangerous to a person’s health,” Caron explains. “Most people are aware that the cross-breeding of plants and species have been happening for centuries – they’re not necessarily new. What is new is the consolidation of the power to use these kinds of technologies into the hands of a very few huge conglomerates.”

Rather than having false impressions about what is happening from a technical perspective, Caron thinks the concerns detractors have around GMOs often have more to do with the business and corporate practices that frame the field. “I think those are perfectly justified and legitimate considerations,” he says. “Right now, a lot of those legitimate complaints about genetically modified organisms simply don’t apply to synthetic biology".

Within the area of synthetic biology, Caron sees a lot of open questions in which researchers are hoping to learn from past mistakes and improve how the production of science takes place. He notes that synthetic biologists still have time to define the relationship between the users and producers of new technologies, and identify ways to diffuse their work to the rest of society.

“It’s a really exciting field to work in – that’s why I’m here.”

‘We’re well placed to be leaders in the area’

Caron examines the public policy, social and ethical factors that shape people’s relationship to technology at Concordia’s Centre for Engineering in Society. He says the centre has an exceptional design that differs from many other institutions across the country.

“All scientists and engineers need ethics and communication training. What happens is that in just about every other Canadian university, institutions outsource these subjects to other areas, such as the philosophy department,” Caron explains. “So, they go take a generic ethics course – as well as a writing course – that’s meant for everybody.”

Through the CASB, Concordia not only has professors and researchers in ethics and communication, but also in the ethics and communication of science and technology.

“We’re really well placed to be leaders in the area of looking at this work in progress that is synthetic biology."


A strong argument for GMO health safety

After more than 20 years of monitoring by countries and researchers around the world, many of the suspicions surrounding the effects of GMOs on organ health, our offspring, and our DNA have been addressed and tested (Figure 1). In the data discussed above, alongside many more studies not mentioned here, GMOs have been found to exhibit no toxicity, in one generation or across many. Though each new product will require careful analysis and assessment of safety, it appears that GMOs as a class are no more likely to be harmful than traditionally bred and grown food sources.

Megan L. Norris is a Ph.D. candidate in the Molecular, Cellular and Organismal Biology Program at Harvard University.

This article is part of the August 2015 Special Edition, Genetically Modified Organisms and Our Food.

References

  1. European Food Safety Authority GMO Panel Working Group on Animal Feeding Trials. “Safety and nutritional assessment of GM plants and derived food and feed: the role of animal feeding trials.,” Food Chem. Toxicol., vol. 46 Suppl 1, pp. S2–70, Mar. 2008
  2. G. Flachowsky, A. Chesson, and K. Aulrich, “Animal nutrition with feeds from genetically modified plants.,” Arch. Anim. Nutr., vol. 59, no. 1, pp. 1–40, 2005.
  3. Cera-gmc.org, ‘Welcome to the Center for Environmental Risk Assessment | CERA’, 2015. [Online]. [Accessed: 11- Jul- 2015].
  4. Tamar Haspel. “Genetically modified foods: What is and isn’t true”. Washington Post. October 15, 2013.
  5. Jeffrey Smith. “GM Potatoes Damaged Rats.” Genetic Roulette, Section I: Documented Health Risks.
  6. G. S. Rhee, D. H. Cho, Y. H. Won, J. H. Seok, S. S. Kim, S. J. Kwack, R. Da Lee, S. Y. Chae, J. W. Kim, B. M. Lee, K. L. Park, and K. S. Choi, “Multigeneration reproductive and developmental toxicity study of bar gene inserted into genetically modified potato on rats.,” J. Toxicol. Environ. Health. A, vol. 68, no. 23–24, pp. 2263–2276, 2005.
  7. Z. L. Chen, H. Gu, Y. Li, Y. Su, P. Wu, Z. Jiang, X. Ming, J. Tian, N. Pan, and L. J. Qu, “Safety assessment for genetically modified sweet pepper and tomato,” Toxicology, vol. 188, no. 2–3, pp. 297–307, 2003.
  8. D. G. Brake, R. Thaler, and D. P. Evenson, “Evaluation of Bt (Bacillus thuringiensis) Corn on Mouse Testicular Development by Dual Parameter Flow Cytometry,” J. Agric. Food Chem., vol. 52, no. 7, pp. 2097–2102, 2004.
  9. D. A. Jonas, I. Elmadfa, K. H. Engel, K. J. Heller, G. Kozianowski, a. König, D. Müller, J. F. Narbonne, W. Wackernagel, and J. Kleiner, “Safety considerations of DNA in food,” Ann. Nutr. Metab., vol. 45, no. 6, pp. 235–254, 2001.
  10. FDA: Guidance to Industry for Foods Derived from New Plant Varieties, Section V (C).

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What are Genetically Modified Organisms? (GMOs)

There is no official definition of a GMO but typically when people call a plant a GMO they mean that part of its DNA has been changed or edited in a laboratory. Scientists change these genes by cutting out genes or adding genes to a DNA sequence. Scientists can also take a gene from one species of plant and put that gene into a plant of a different species. Plants made by using this lab technique are called ‘transgenic’ (trans- means across and -genic means related to genes).

Plants and animals become ‘genetically modified’ in nature too. Whenever animals or plants reproduce sexually, the DNA of the parents are combined. Therefore every plant and animal is genetically unique from its parents. Mutations in the DNA sequence occur naturally when cells divide and sometimes these mutations get passed onto offspring. These mutations can create sequences that never before existed in that species.

Grapefruit is a type of plant that was created through hybridization. Click for more information.

Sometimes during pollination the DNA of two different species of plants can combine to create hybrid plants. This happens in the wild but farmers also make hybrid plants on purpose. These hybrid plants contain new combinations of DNA that can cause a plant to look very different from either of its parents. Examples of hybrid plants are grapefruit (cross between orange and pomelo), some types of corn, wheat, and bananas. Animals can also be hybrids. A mule is a hybrid of a donkey and a horse.

You could argue that almost all the plants we eat are GMOs. Although the DNA of most types of bananas, tomatoes, and corn were not altered in a lab, their DNA has been highly modified for more than 10,000 years through selective breeding by humans. Humans chose to grow plants they discovered in the wild that had mutations that made the plants tastier or more colorful. Over many generations of breeding these mutant plants, our modern farmed plants look and taste nothing like their wild ancestors.

So what makes golden rice so controversial? Golden rice is transgenic – the genes that were added to make beta-carotene in the rice come from bacteria and corn. The extra genes added to golden rice are found in harmless bacteria and in other plants that are safe to eat. While protestors still think this makes the rice unsafe to eat, scientists have not found any evidence that the rice is harmful. Research is also showing that growing GMOs may be beneficial for farmers.


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